Electrical terminal



March 15, 1938 H. J. BLAKESLEE ELECTRICAL TERMINAL Filed Jan. 14, 1957 Patented Mar. 15, 1938 UNITED STATES PATENT OFFICE 10 Claims.

This invention relates to the construction of spring-jaw electrical terminals which are particularly adapted for knife blade switches, al though serviceable for snap switches and other electrical devices which have clips for receiving and irictionally retaining conductors.

The object of the invention is the provision of a terminal which is cheap to manufacture and assemble which will easily receive a blade but will always engage an inserted blade with a strong tension and thereby ensure an efficient electrical contact between terminal and blade.

In attaining this object the terminal jaws are first bent toward each other and given such an initial or pre-set that their free ends, which are longitudinally slotted, will engage each other with a strong force. Following this a pin with.

an enlargement or collar at its middle and with or without enlargements or heads at its ends is pressed into the slots in the ends of the jaws.

The collar at the middle of the pin is of such shape and size that it will separate the pre-set law ends somewhat less than 'the thickness of the blade to be received, and the heads, if provided, at the ends of the pin are so shaped and spaced that they will allow the jaw ends to spring out slightly when a blade is inserted in the jaws but will prevent the jaws from being separated so widely that an eflicient engagement with a blade will not be achieved, whereby the jaws will be separated sufficiently to receive a blade but will be always under such great tension that a blade will be strongly grasped and eflicient electrical contact ensured.

In the accompanying drawing Fig. 1 shows a side view of a closed knife-blade switch that has return bend terminals constructed according to the present invention. Fig. 2 is an end view of the closed switch. Fig. 3 is a side view of the same switch opened. Fig. 4 is an end view of the opened switch. Fig. 5 is an enlarged view of the terminal jaws in their pre-set relation. Fig. 6 is a section of the jaws with a pin inserted. Fig. 7 is a section on the plane 1-'I on Fig. 6. Fig. 8 is a view of the free end 01' one of the jaws before it is given its return bend and showing the slot therein. Fig. 9 is a view of a terminal with straight jaws in their pre-set relation. Fig. 10 is a section of the straight jaw terminal with a separating pin inserted.

The switch illustrated has a base I of insulating material on which are secured in any suitable manner the conducting terminals 2 and 3.

The preferred type of terminal comprises a bottom section 4 adapted to be secured to the base and side sections 5 that rise from the bottom section and that have return-bend ends 6 which form the jaws of the terminal. The free ends of the jaws are provided with longitudinal slots 1. The side sections are bent and set so that the free ends are brought together with considerable force, as illustrated in Fig. 5.

The pin 8 which is of a diameter that allows it to be inserted in the slotted ends oi? the jaws, has a collar 9 midway of its length and has headed ends ID. The collar is larger in diameter than the width of the slots and is of such thickness that when the pin is inserted in the slots in the ends of the Jaws it will separate the Jaws but inot as much as the thickness of the blade H which the jaws are intended to receive. The heads at the ends of the pin are larger in diameter than the width of the slots and are spaced apart such a distance that they will allow the laws to spring open when a blade is inserted between them but will prevent the jaws from becoming accidentally or otherwise opened to such an extent that the blade when inserted between them will not be strongly grasped by the jaws.

It is preferred that the width of the outer length II of the slots in the free ends of the Jaws shall be a little greater than the width of the inner length l3 of the slots, as illustrated in Fig. 8. Also that the width of the outer length l2 of the slots in the ends of the jaws shall be practically the same as the length of the diameter of the pin, and that the width of the inner lengths l3 of the slots shall be slightly less than the diameter of the pin. Under these circumstances when a pin is thrust into the slots of the bent jaws not only will the central collar separate the jaws but the pin will also transversely spread the sections of the jaws separated by the narrower length of the slots until the pin reaches the wider lengths of the slots and allow the sections of the jaws to spring back to normal position, then the pin cannot be readily withdrawn from the slots after it has once been located in position, as illustrated in Fig. 7.

The modified terminal illustrated in Figs. 9 and 10 has straight Jaws l5, rather than returnbend Jews, as above described. The jaws are slotted. and inserted in the slots is a pin I6 with a separating enlargement or collar II. Restraining heads are omitted from the pin l6, as they may be from the pin 8 previously described.

The terminals described may be used without change of construction to provide the hinge terminal of a switch and also the make and break terminal oi a switch. When these terminalsare used for a knife switch may be pivoted on the that the other end will be capable of movement into and out of the other terminal, the blade being placed on the pin before it is inserted in the terminal jaws. The blade shown has a slot ll which when the blade is closed ilts down over the pin in the make and break terminal, which pin provides a stop for this end of the blade.

The construction described eliminates the employment of any screws, washers, bolts and nuts for retaining the blade, or keeping the jaws in shape. Although the terminal jaws are separated by the collar on the pin sufllciently to allow the blade to be readily entered between them, owing to the heavy closing pre-set given the jaws, the jaws strongly press against the sides of the blade and thus contact between a blade and the terminals is always eillcient.

The invention claimed is one end oi the blade Ii pin in one terminal so 1. An electrical terminal comprising return bend spring-jaws and a pin extending transversely through and having its ends supported by said jaws, said pin bearing means between the yielding ends of said jaws for separating the jaws against an initial closing tension.

2. An electrical terminal comprising return bend spring-jaws and a pin extending transversely through and having its ends supported by said jaws, said pin bearing means between the yielding ends oi said jaws for separating the jaws against an initial closing tension and having means at its ends for preventing the jaws fro-m abnormal separation.

3. An electrical terminal comprising return bend spring-jaws and a pin extending transversely through and having its ends supported by said jaws, said pin bearing an enlargement at its middle between the yielding ends of said jaws for separating the jaws against an initial closing tension and bearing enlarged ends outside of the jaws for preventing the jaws from abnormal separation.

4. An electrical terminal comprising return bend spring-jaws having longitudinally slotted ends and a pin inserted in and extending transversely through said slotted ends, said pin bearing means between the yielding ends of said jaws for separating the jaws against an initial closing tension.

5. An electrical terminal comprising return bend spring-jaws having longitudinally slotted ends and a pin inserted in and extending transversely through said slotted ends, said pin bearing means between the yielding ends of said laws for separating the jaws against an initial closing tension and bearing means outside of the from abnormal sepjaws for preventing the jaws aration.

6. An electrical terminal comprising longitudinally slotted spring-jaws, and a pin held in said slots and extending transversely through said jaws, said pin bearing means between said jaws for separating the jaws against an initial closing tension, the width of the sections of said slots at their outer ends and at their inner ends being substantially the same as the diameter of said pin where it extends through the slots and between said sections being slightly less than the diameter of said pin.

7. An electrical terminal comprising longitudinally slotted spring-jaws, and a pin held in said slots and extending transversely through said jaws, said pin bearing means between said jaws for separating the jaws against an initial closing tension and bearing means for preventing the jaws from abnormal separation, the width of the sections of said slots at their outer ends and at their inner ends being substantially the same as the diameter of said pin where it extends through the slots and between said sections being slightly less than the diameter of said pin.

8. A switch comprising two spring-jaw terminals, a pin extending transversely through and supported by the jaws of each terminal, each of said pins bearing means between the yielding ends 0! said jaws for separating the jaws against an initial closing tension, and a blade pivotally mounted on the pin between minal and adapted to be turned into and out of engagement with the jaws of the other terminal.

9. A switch comprising two spring-jaw terminals, a pin extending transversely through and supported by the jaws of each terminal, each of said pins bearing means between the yielding ends of said jaws for separating the jaws against an initial closing tension and bearing means for preventing the jaws from abnormal separation. and a blade pivotally mounted on the pin between the jaws of one terminal and adapted to be turned into and out of engagement with the jaws of the other terminal.

10. A switch comprising two similar terminals each consisting of a pair of return bend pre-tensioned longitudinally slotted spring-jaws, said slots being wider at their ends than at the bends oi the jaws, a pin extending transversely through the wider sections of said slots and retained therein by the narrower sections of said slots, said pin bearing means for separating the jaws with which they are associated against the pre-closing tension, and a blade pivotally mounted on the pin in the jaws of one terminal and adapted to be swung into and out of engagement with the jaws of the other terminal.

HENRY J. BLAKESLEE. 

